New Thermostable Amylase from Bacillus cohnii US147 with a Broad pH Applicability

• Published in: Applied biochemistry and biotechnology Vol. 157; no. 1; pp. 50 - 60
• Main Authors: Ghorbel, Raoudha Ellouz, Maktouf, Sameh, Massoud, Ezedine Ben, Bejar, Samir, Chaabouni, Semia Ellouz
• Format: Journal Article
• Language: English
• Published: New York New York : Humana Press Inc 01-04-2009; Humana Press Inc; Springer; Springer Nature B.V
• Subjects: amylases; Amylases - chemistry; Amylases - isolation & purification; Amylases - metabolism; Bacillus; Bacillus - enzymology; Bacillus - growth & development; Bacillus - isolation & purification; Bacillus - metabolism; Bacillus cohnii; Bacteria; Biochemistry; Biological and medical sciences; Biotechnology; calcium; Chemistry; Chemistry and Materials Science; EDTA (chelating agent); enzyme activity; enzyme inhibition; Enzyme Stability; Enzymes; Fundamental and applied biological sciences. Psychology; Hydrogen peroxide; Hydrogen-Ion Concentration; Kinetics; molecular weight; polyacrylamide gel electrophoresis; Polymers; purification; saccharification; soil bacteria; Starch; Substrate Specificity; Substrates; Temperature; thermal stability; thermophilic bacteria; zinc; Tunisia; Characterization; Purification; Amylase; Acid and basic pH activity; Bacillus cohnii . Amylase; Enzyme; Bacillaceae; Thermal stability; Bacillales; Bacillus; pH; Bacteria; Purification . Characterization
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-008-8278-0

A new thermophilic bacterial strain identified as Bacillus cohnii US147 was isolated from the southern Tunisian soil. The identification was based on physiological tests and molecular techniques related to the 16S ribosomal ribonucleic acid. The isolated strain produced amylase, which was purified. This amylase had an apparent molecular mass of 30 kDa as estimated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Amylase US147 showed K m and V max values of 0.7 mg/ml and 2.2 U/ml, respectively, with starch as the substrate. The enzyme was active in acid and basic pH and had a maximal activity on starch at pH 9 and 70 °C. The enzyme was stable at pH 9 for 72 h and retained half of its activity after incubation at 70 °C for 150 min. A partially inhibition (15%, 25%, 23%, 20%, and 22%) was obtained with 1 mM SDS, 1 mM NaBO₃, 1 mM H₂O₂, 1 mM Zn⁺², and 5 mM ethylenediamine tetraacetic acid (EDTA), respectively. The amylase recovered its original activity by the addition of 10 mM Ca ²⁺ to the 5 mM EDTA. These properties indicated a possible use of this amylase in starch saccharification, in detergent, and in other industrial applications.